MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 28
ARTICLE http://dx.doi.org/1 0.431 4/mcd.v1 0i3s.5 Water hyacinth (Eichhornia crassipes), any oppor- tunities for the Alaotra wetlands and livelihoods?
Tsiry F. RakotoarisoaI, Patrick O. WaeberII, III, Torsten Correspondence: RichterI, Jasmin Mantilla-ContrerasI Tsiry F. Rakotoarisoa Ecology and Environmental Education Group, Institute of Biology and Chemistry, Hildesheim, Germany E-mail: [email protected]
ABSTRACT institutionnelles et financières de Madagascar. L’utilisation de la Species invasions are one of the world’s most severe conserva- jacinthe d’eau, comme fertilisants, fourrage ou dans la production tion threats. The invasive water hyacinth (Eichhornia crassipes) is artisanale, pourrait représenter une alternative pour améliorer les one of the most troublesome plants in the world. It appears in moyens de subsistance de la population locale. Au cours de cette over 50 tropical and subtropical countries. This plant species étude, des données socioéconomiques touchant les parties pre- causes several ecological and socioeconomic problems affecting nantes des zones humides de l’Alaotra ont été collectées dans ecosystems and local livelihoods. The water hyacinth occurs in trois localités qui se différencient au niveau de la dégradation de the Alaotra wetlands encompassing the largest lake of Mada- l’habitat naturel (Anororo, Andreba et Vohimarina). Les objectifs de gascar. The Alaotra region is renowned as Madagascar’s bread cette recherche consistent d’une part à décrire des différents basket as it is the biggest rice and inland fish producer. The cur- moyens de subsistance locale et d’autre part à identifier les mo- rent study collected socioeconomic data from the Alaotra wetland teurs et barrières de l’utilisation de la jacinthe d’eau. Le contexte stakeholders within three locations around Lake Alaotra to général affectant la sécurité des moyens de subsistance pourrait contextualize local livelihoods and to identify the drivers and bar- bloquer l’acceptation de l’utilisation de cette plante. Cependant riers for the utilization of this plant. Methods of control seem to be l’information ainsi que des supports financiers et techniques pour unrealistic due to institutional and financial limitations in Mada- les parties prenantes locales sont des moteurs importants pour gascar. Using the plant as fertilizer, animal fodder or for handi- encourager l’usage de la jacinthe d’eau au niveau du lac Alaotra. crafts seems to represent a feasible alternative to improve the livelihood of the local population. However, local concerns about INTRODUCTION livelihood security may hinder acceptance of such new alterna- The water hyacinth (Eichhornia crassipes, Pontederiaceae) is an tives. Providing information as well as financial and technical sup- aquatic plant, originating from the Amazon Basin. It is listed by port to local stakeholders may help encourage the use of the IUCN as one of the “1 00 most invasive species” in the world (Lowe water hyacinth in the Alaotra region. et al. 2000) due to its high reproduction rate, the complex root structure and the formation of dense mats with up to two million RÉSUMÉ plants per hectare (Gopal 1 987, Villamagna and Murphy 201 0). The Les espèces envahissantes ont été récemment identifiées comme water hyacinth is to date recognized as invasive in over 50 tropi- l’une des principales menaces pour la protection de la biodiversi- cal and sub-tropical countries on five continents (Africa, Australia, té. La jacinthe d’eau (Eichhornia crassipes) est l’une des plantes Asia and America and for Europe in Portugal) (Gopal 1 987, Vil- envahissantes les plus problématiques au monde. Elle est connue lamagna and Murphy 201 0). The spreading of the plant can lead to dans plus de 50 pays tropicaux et subtropicaux. Cette plante est great ecological, social and economic problems (Kull et al. 201 4). la source de nombreux problèmes écologiques et économiques et The plant can reduce light and oxygen leading to deteriorating wa- affecte par conséquent les écosystèmes ainsi que les moyens de ter quality, increase water loss due to high evapotranspiration and subsistance des populations humaines des régions concernées. thus negatively affect the flora and fauna. Moreover it can hinder Elle est rencontrée au niveau des zones humides de l’Alaotra en- transportation, fishing and block intakes for hydropower and irri- globant le plus grand lac de Madagascar, le premier grenier à riz gation schemes affecting therefore the livelihood of local com- de l’île et qui tient une place importance pour la pêche. Les mé- munities (Calvert 2002). Furthermore, the water hyacinth thodes pour contrôler la prolifération des jacinthes d’eau represents a microhabitat for disease vectors (snails for bilharzia semblent ne pas pouvoir être appliquées à cause des limitations or Anopheles sp. for malaria) and therefore constitutes a threat to
I Ecology and Environmental Education Group, Institute of Biology and Chemistry, Marienburger Platz 22, 31 1 41 Hildesheim, Germany II Madagascar Wildlife Conservation, Lot 1 4433 Atsimondrova, Ambatondrazaka 503, Madagascar III ETH Zurich, Ecosystems Management, Forest Management and Development Group, Universitaetstrasse 1 6, 8092 Zurich, Switzerland
Citation Rakotoarisoa, T. F., Waeber, P. O., Richter, T. and Mantilla-Contreras, J. 201 5. Water hyacinth (Eichhornia crassipes), any opportunities for the Alaotra wetlands and livelihoods? Madagascar Conservation & Development 1 0, S3: 1 28–1 36. (doi:1 0.431 4/mcd.v1 0i3s.5) Madagascar Conservation & Development is the journal of Indian Ocean e-Ink. It is produced under the respon- sibility of this institution. The views expressed in contri- butions to MCD are solely those of the authors and not those of the journal editors or the publisher.
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Missouri Botanical Garden (MBG) Madagascar Research and Conservation Program BP 3391 Antananarivo, 1 01 , Madagascar MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 29
human health (Masifwa et al. 2001 , Plummer 2005). ding hills are dominated by open grasslands and subject to Globally, a number of methods are used to manage and cont- continuous erosion. This leads to the reduction of the lake water rol the water hyacinth: the manual and mechanical control re- surface by sedimentation (Raharijaona-Raharison and Randrianari- quires high expenses. In China, removing water hyacinth comes at son 1 999, Wright and Rakotoarisoa 2003, Bakoariniaina et al. a cost of more than US$ 1 2 Million per year (Jianqing et al. 2001 ). 2006). In the last 30 years, Lake Alaotra has lost 5 km2 in size (Ba- Chemical control, using 2,4-D or glyphosate, is seemingly a more koariniaina et al. 2006). Fish catches (4,000 tons in 1 960 to economically feasible option. In the USA, chemical control is esti- 2,000 tons in 2004) are declining due to overfishing. Rice produc- mated to cost US$ 1 83 per hectare (Charudattan et al. 1 996). Ho- tion decreased by approximately 40% in recent years due to de- wever, in many countries public opinion is strongly against the use posits of sand and infertile laterite in poorly maintained irrigation of chemicals in water bodies, which are oftentimes used for drin- systems and deterioration of fertile soils (Pidgeon 1 996, Rakoto- king purposes (ibid). Biological control, though less widely applied, nierana 2004, Razanadrakoto 2004, Bakoariniaina et al. 2006). uses the weevil species Neochetina eichhornia, N. bruchi and the Consequently, reduced incomes are further exacerbating the moth Sameodes abligutallis which adults feed on water hyacinth pressures on the remaining marshlands. leaves and the larvae tunnel in petioles (Coetzee et al. 2009). Pa- According to Lammers et al. (201 5), the water hyacinth is thogens can also be used to control the water hyacinth. In Egypt, found everywhere on Lake Alaotra, building occasionally thick and the fungus Alternaria eichhornia was condensed in cottonseed oil dense mats spanning hundreds of square meters. The plant, ho- emulsion and spread on the water hyacinth killing 1 00% of the wever, is barely used in the region; a few people occasionally use plants seven weeks after application (Shabana et al. 1 995). Bio- it to produce compost, to feed pigs and geese and for installing control is economically feasible and environmentally viable but re- fish traps on the mats. It is currently unclear to what degree the quires several years of implementation (Charudattan et al. 1 996). water hyacinth in the Alaotra region is affecting local livelihoods As an alternative to mechanical, chemical or biological cont- (sensu Chambers and Conway 1 991 ), or whether the plant could rols, the economic utilization of this invasive plant has to be be used systematically and economically by a wider range of sta- considered. Globally, the water hyacinth is used in China, Indone- keholders. The objective of this study is to identify the potential sia, India, Malaysia, Bangladesh, Sri Lanka, Thailand, Philippines drivers and barriers to the use of water hyacinth by depicting the and in some African countries such as Kenya and Nigeria for pro- socioeconomic conditions of the concerned local stakeholders. ducing fertilizers, handicrafts, paper, biogas, fodder, briquettes, The basic assumption is that the plant has negative ecological and furniture and to clean industrial waste water by phytoremediation economic impacts. Using the plant as an additional source of in- (Jafari 201 0, Ndimele 201 1 , Patel 201 2). However, in remote poor come could potentially benefit a wider range of stakeholders; this regions in developing countries the use of water hyacinth is hin- could alleviate its possible impacts and diminish pressure on the dered by absence of electricity, lack of technology and poor infra- marshland ecosystem. A typology of the main stakeholders of the structure (e.g., Gunnarsson and Petersen 2007). Alaotra wetlands is provided to describe the qualitative and The water hyacinth (vernacular name: tsikafona or tsikafoka) quantitative features of local livelihoods. An assessment of the lo- occurs in Madagascar’s largest wetland, located in the Alaotra- cal population’s perception and knowledge of water hyacinth as Mangoro region encompassing about 23,000 ha of freshwater well as current and potential usages are discussed. marshes. Lake Alaotra is the largest freshwater lake in Mada- gascar (20,000 hectares of open water); with an average depth of METHODOLOGY 1 –1 .5 m, it is a very shallow lake (Ferry et al. 2009). The natural fre- Field work was conducted from November 201 2 to April 201 3 in shwater marshes fringing the lake are dominated by common the Lake Alaotra region. Three study sites were chosen according reed (vernacular name: bararata) (Phragmites australis) and cype- to the level of marsh degradation (cf. Lammers et al. 201 5): Vohi- rus (vernacular name: zozoro) (Cyperus madagascariensis). The marina (E48° 32’ 59.7”, S1 7° 20’ 02.4”, 761 m), situated on the marsh vegetation supports endemic species such as the Alaotran north shore of the lake, with about 500 inhabitants, entails 302 gentle lemur (vernacular name: bandro) (Hapalemur alaotrensis) hectares of intact marsh vegetation. Anororo (E48° 26’ 01 .4”, which is the only permanent swamp living primate in the world S1 7° 30’ 44.0”, 724 m) on the western coast of the lake has over (Andrianandrasana et al. 2005, Ralainasolo et al. 2006, Guillera-Ar- 8,000 inhabitants, and encompasses over 9,850 hectares of mar- roita et al. 201 0, Waeber et al. In press). The water hyacinth occurs shland vegetation. Andreba Gare (E48° 30’ 08.0”, S1 7° 37’ 51 .7”, in both the open water where it is freely floating and moved by 739 m), located in the eastern part with 4,000 inhabitants, winds as well as in the marsh vegetation. contains 235 hectares of marshes (Andrianandrasana et al. 2005). The water hyacinth has been introduced to Madagascar at Qualitative and quantitative data focusing on socioeconomic the beginning of the twentieth century as ornamental plant (Bing- conditions and the use of water hyacinth were collected using geli 2003) and was identified later as serious threat by Perrier de two methods: group surveys and semi-structured interviews. Oral la Bathie (1 928). Goarin (1 961 ) reported that the plant was already information from the village heads (chef fokontany) was conside- present in the Lake Alaotra during the period of French coloniza- red to identify and select the main local stakeholders (sensu Reed tion. 2009) of the Alaotra wetland system. Group surveys (cf. McNama- Lake Alaotra is home to over 560,000 people who live along ra 2003) were conducted to assess the socioeconomic conditions its shores (INSTAT 201 3). Rice cultivation and fishing constitute the for each of the households of the four stakeholder groups (rice main income in the region, resulting in an increasing pressure on cultivators, fishers, vegetable farmers and cattle breeders). Twelve the marshlands (Ralainasolo et al. 2006, Copsey et al. 2009). To meetings representing each of the four resource user groups support a steadily growing human population in the region, many were organized in the three study sites with a total of 1 20 stake- marshlands have been converted into rice fields during dry sea- holders. The survey covered livelihood characteristics such as the son when the water level is low (Ranarijaona 2007). The surroun- individual daily income, the description of targeted resources (e.g., MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 30
fish or rice), the type and use of equipment and application of res- ter bucket (ca. 1 6 kg) of common carp costs US$ 25, while tilapia pective techniques as well as time allocation, associated invest- or Asian snakehead brings US$ 1 8 and the Alaotra rainbow fish ments, costs and benefits and the encountered daily livelihood (vernacular name: katrana) (Rheocles alaotrensis) sells for US$ 1 0 challenges (cf. Supplementary Material). on the local markets. Official fishing activity requires a license Semi-structured one-on-one interviews (Bernard 2005) were from the fisheries state department which can be obtained for an conducted to assess the potential drivers and barriers of the use annual fee of US$ 5. Fishermen are organized in federations en- of the water hyacinth. Again, a total of 1 20 stakeholders (others compassing several associations. The federations control the than the ones engaged in the survey) were interviewed (rice mesh size diameter and fishing activities during the period of fi- cultivators, fishermen, vegetable farmers and cattle breeders). The shing closure (1 5 November to 1 5 January) during which only sub- interview was subdivided into (i) personal perception of resources sistence fishing is allowed. A majority of fishermen, however, do and value system; (ii) assessment of personal attitudes through not have permits and many do not respect the fishing closure due the depicting of possible future resource use scenarios; (iii) awa- to a lack of alternative income. reness and potential use of the water hyacinth as an alternative source of income (cf. Supplementary Material). RICE CULTIVATORS. Rice represents the most important crop All data were analyzed using MAXQDA 201 1 , a qualitative da- production in the Alaotra region and therefore constitutes ta analysis software. This software is designed to facilitate qualita- the main subsistence and source of income of the farmers (Du- tive data analysis by coding and categorizing the answers crot and Capillon 2004). In general, a rice field can be under tradi- expressed by each interviewee. tional irrigation systems or modern systems of irrigation with dams and canals (mailles) allowing reliable water control and sup- RESULTS ply. Rice cultivation occurs mainly in lowland parcels (rizières) and STAKEHOLDER TYPOLOGY. The main stakeholders at Lake occasionally in upland parcels (tanety) and forest plots during the Alaotra were fishermen and rice cultivators. A majority, ho- rainy season (January–June, vary taona) and in former marshes wever, had several activities (e.g., vegetable farming and breeding) converted into rice fields during the dry season (July–December, and depend on the marshes for arable land and for obtaining se- vary jebo); cf. Ducrot and Capillon (2004) for detailed farming typo- veral plant species for their livelihoods. Cyperus (Cyperus mada- logy. The first investments required for rice cultivation are the gascariensis) is the most widely used plant species in this region, acquisition (or leasing) of land, seeds, pesticides and tools. and together with the common reed (Phragmites australis), are Planting one hectare of rice requires 1 5 kg of seeds costing bet- deeply rooted in Sihanaka tradition and used for constructing ween US$ 3.5–5; currently, there are more than ten different types houses, fences, animal shelters, handicrafts, fish traps as well as of rice in use (Ducrot and Capillon 2004). The most common tools during traditional ceremonies (Rendigs et al. 201 5). used in rice cultivation are spades (angady, US$ 4), ploughs Across the three study sites, 38% of the stakeholders inter- (US$ 1 50), small tractors (kibôta) (US$ 4,500), carts for transporting viewed (n=46) earn less than US$ 2.5 per day (exchange rate the harvest ($US 500), and weeders (US$ 1 0). Rice cultivation MGA/USD=2,884), 60% (n=72) earn US$ 2.5 to US$ 5 and 2% re- consists of various activities such as irrigating and ploughing the presented by retired officials (n=2) earn more than US$ 5. In soil, direct seeding or transplanting the sprouts, irrigating the contrast, 60% (n=72) of the stakeholders stated that they cannot fields and discarding the weeds manually or with chemicals. The make ends meet, 30% (n=37) could but only without mishaps, 8% daily salary for workers in the rice fields ranges from US$ 1 .5–3. (n=9) with difficulties and 2% represented by the same retired offi- The rent of land can either be paid in cash or in part of harvest: cials (n=2) do not have problems to ensure their livelihoods. Most the landowner usually earns one ton of rice per hectare without individuals therefore are already under severe economic stress. working with the lender or 1 .5 tons when working with the lender. The tenure contract also includes responsibilities for both lessee FISHERMEN. Only practiced as source of local subsistence a and lessor regarding input, labor and equipment (Jacoby and century ago, fishing in the Alaotra developed gradually with Minten 2007). One hectare of rice field produces about three tons the introduction of fishnets and opportunities created by the rail- of rice. The yield is attributed more for self-subsistence than for road for selling fish outside the region (Moreau 1 979). Several cash income. One kilogram of rice on local markets costs about types of fishing tools exist at Lake Alaotra; their use depends on US$ 0.4. Water supply and control represent the main issues of the targeted species and on the season. The fishing nets are ge- rice cultivation in the Alaotra (Ducrot and Capillon 2004). nerally used year-round and target various fish species according to the mesh size. The fishing rods (fintana), spears, sticks (jorira) VEGETABLE FARMERS. Though negligible compared to rice and fish traps are mainly used during the rainy season as long as cultivation in terms of cultivated surface and production, ve- high water levels allow their usage. Fish traps and fishing nets are getable farming produces enough vegetables for the Alaotra re- the most common tools. A single fish trap and one kilometer of fi- gion and supplies for other regions of Madagascar (Monographie shing reel sell for US$ 0.75 and US$ 3.5, respectively. Depending Régionale 2003). In contrast to rice, vegetables are produced on the size a canoe sells for US$ 35–1 00. Fish catch is now reser- mainly for cash income. Collectors from the cities buy and export ved mainly for cash income rather than subsistence. The fish price vegetables to the islands around Madagascar. The main invest- depends on the season (and peaks during the period of rice har- ments for planting vegetables are the seeds (3 sachets for US$ 1 ), vesting), the buyers (local or national collectors) and the targeted tools (e.g., spade), cow dung (US$ 4.5 per one cart) and to have a species (Copsey et al. 2009). The common carp (vernacular name: well built for the water (US$ 60). Compost is rarely used compared besisika) (Ciprinus carpio) is the most expensive fish followed by to the cow dung because it needs extra preparation. However, Tilapia spp. (vernacular name: lapia) (Cichlidae) and the Asian sna- cow dung is relatively rare and expensive (US$ 4.5 per cart). One kehead (vernacular name: fibata) (Channa maculata). A full ten li- hectare of field needs ten carts of cow dung. Therefore it is com- MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 31
bined with industrial fertilizers and pesticides. Vegetables are This is accentuated in particular in Vohimarina, the least degraded planted in the lake shore during the dry season (May to Novem- site with lowest abundance of water hyacinth (Lammers et al. ber). However, onions, beans and peanuts are still planted during 201 5), where more than 93% of the stakeholders have never used the rainy season. As for the rice cultivation, the rent of land can water hyacinth. The rest of the stakeholders occasionally used the be paid in cash or in part with the harvest. plant for fish trapping, pig farming or compost production (Table 2). BREEDERS. Breeding represents a food and income source as (iv) How can the water hyacinth be used? This question as- safety net against stress and shock for the Alaotra farmers. sesses the stakeholders’ knowledge on potential benefits deriving The majority of breeders have zebus, pigs and poultry (e.g., chi- from this plant. 67% of the respondents would use water hyacinth cken, ducks and geese); only few are breeding sheep and goat. either as a source for composting, mulch, fodder, handicraft and During day time, the animals (except pigs) are let free and kept in- water purification (Table 2). Local composting consists of mixing side shelters in the villages during night hours because of even- fresh water hyacinth with cow dung. Mulching this plant consists tual thieves (dahalo). Zebu in the Alaotra region represents, as in in spreading chopped fresh water hyacinth before planting rice in other parts of Madagascar, a banking system (Kaufmann and Tsi- the fields. Pigs and geese feed on this plant. Pigs eat the whole rahamba 2006); they are used for milk production and work (e.g., plant except the roots whereas geese feed only on the leaves. pulling a plough for rice production). A zebu is butchered or sold Handicrafts are made with dry water hyacinth stems. Thirty-three on the local market only in circumstances where money is nee- percent of the stakeholders do not see any possible use of this ded, e.g., for cultural purposes such as marriage or funerary tradi- plant. tion famadihana. A male adult zebu costs between US$ 250–400, (v) What would you do if the entire lake would be covered an adult pig costs about US$ 200. The lack of income decreases with water hyacinths? This question intends to test the creativity the investments into animal care such as vaccines and proper and willingness of resource users to using the plant in an extreme supply of animal food. scenario. Only 1 6% of the interviewees would use the water hya- cinth as compost and handicrafts; in contrast, all other proposed DRIVERS AND BARRIERS OF WATER HYACINTH UTILIZATION. In activities are either laborious and/or financially costly and without order to assess possible drivers and barriers for using water any economic gain for the stakeholders (Table 3). hyacinth in the Alaotra region, a survey with five questions was administered. DISCUSSION (i) What are the most invasive plant species in the Alaotra POTENTIAL THREATS. Extensive use of chemical fertilization wetlands? This question intended to unveil the stakeholders’ for agricultural production around wetlands leading to an in- knowledge related to the marshland ecosystem. Due to the ambi- crease of nutrient concentrations of water bodies (eutrophication) guity of the term ‘invasive’ (Kull et al. 201 4) it was presented as and combined with high solar energy (Ndimele et al. 201 1 ) re- plant species that spread rapidly in the area and with potentially present favorable conditions for the spread of the water hyacinth negative impacts on the livelihood of local stakeholders. Accordin- (Charudattan et al. 1 996). These conditions are found at Lake Alao- gly, water ferns (vernacular name: ramilamina) (Salvinia spp. ) (40%) tra (Pidgeon 1 996). High water temperatures peaking more than and the water hyacinth (36%) are considered as most abundant 41 ˚C have been measured in the littoral zone of the lake (Lammers and harmful species for rice cultivation and fishing in the Alaotra et al. 201 5) and are further favoring the spread of water hyacinth wetlands (Table 1 ). A few participants (4%) affirm that there is no and depleting dissolved oxygen (Gratwicke and Marshall 2001 ). invasive plant species in the wetlands. The thick mats of water hyacinth lead to a decrease of phyto- (ii) What are the current negative impacts caused by the wa- plankton (due to light deprivation), an increase in water turbidity ter hyacinth in the Alaotra region? Nineteen percent of the stake- (due to the constant rotting of the mat base) and a decrease of holders stated not to be affected by the water hyacinth. All dissolved oxygen (due to the high oxygen consumption of rotting impacts listed by the participants represented mainly visible clues plant biomass) (Masifwa et al. 2001 , Rommens et al. 2003, Man- such as waterway clogging (63%) and invasion of rice fields (1 4%). gas-Ramírez and Elías Gutiérrez 2004, Perna and Burrows 2005, The rest of opinions (4%) were the bad smell generated by de- Villamagna and Murphy 201 0). Collectively these effects may ne- caying water hyacinth, decrease of space for fishing occupied by gatively impact animal and plant species at Lake Alaotra. The im- the plant, reduction of fish catches due to waterway clogging and pacts of water hyacinth on invertebrate communities are variable: destruction of fish nets by the plant and water flows decrease due A greater number of invertebrates is observed in the transition to thick mats of water hyacinth. Table 2. Current and Potential usage of water hyacinth expressed by stakeholders (iii) How do you use the water hyacinth in your daily life? This during interviews (n=1 20) within the three study sites (Vohimarina, Andreba and question intends to assess the awareness for this plant in the re- Anororo). Current uses do not reflect the potential uses. gion. Most of the stakeholders have never used this plant (89%).
Table 1 . Plant species in the marshes identified by respondents (n=1 20) as covering large areas and having negative impacts within the three study sites. MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 32
Table 3. Proposed management actions in case of total invasion of the Lake loss by the water hyacinth leads especially in shallow lakes such Alaotra by the water hyacinth (n=1 20) within the three study sites (Vohimarina, as Lake Alaotra to a drop in water level. In turn this can add an ad- Andreba and Anororo). The majority of the actions do not generate economic benefits. ditional stress to the hydrologic balance in the region (Ferry et al. 2009), which constitutes another factor further stressing the rice production in the wetlands. A reverse effect could happen during periods of heavy rain or cyclones. By clogging waterways the wa- ter hyacinth can slow down the water flow up to 95% leading to severe flooding (Jones 2009). The management of the water hyacinth requires prior esti- mations of the current state of invasion to evaluate the costs. Sha- ckleton et al. (2007) created models about invasive species zone from E. crassipes stands to open water due to increased characterized by the time since invasion, abundance and level of structural diversity as compared to open water zones (Masifwa et cost and benefits. The models can be used as a tool to guide al. 2001 ). However, the total amount of invertebrates decreases interpretation and future management of invasive species and si- because of the overall reduced availability of phytoplankton (Toft multaneously assessing vulnerabilities of local populations toward et al. 2003, Midgley et al. 2006). The decrease of invertebrates re- the invasive species. According to classifications and procedures portedly leads to reduced fish diversity (Howard and Harley 1 998, used in the model and combined with our findings from the Alao- Gratwicke and Marshall 2001 ). As with the invertebrate communi- tra in this study, the water hyacinth can be defined as a “undesi- ties, the impacts of the water hyacinth on waterbirds are ambiva- rable, strongly competitive species” Shackleton et al. (2007: p 1 24). lent: The positive effects of the water hyacinth on the invertebrate Regarding time since invasion, the water hyacinth invasion in the communities could lead to higher diversity and density of water- Alaotra seems to be in ‘phase 2’: rapid spreading thanks to its birds whereas dense mats of water hyacinth or the low dissolved competitive nature. Awareness of the water hyacinth increases as oxygen under the mats could physically hinder waterbird access it becomes first a nuisance, and later on a significant hindrance to to prey or impact negatively the abundance of the prey species local livelihood activities and options (e.g., rice cultivation and fi- (Villamagna and Murphy 201 0). At Lake Alaotra, several bird spe- shing activity in the Alaotra). The future costs (ecological, aesthe- cies such as the white backed duck (Thalassornis leuconotus in- tic, harvesting, and control) are increasing rapidly thus reducing sularis) suffer from the spread of the water hyacinth (Nicoll and the productivity of other resources; hence, the vulnerability of the Langrand 1 989). Due to its strong competitiveness regarding light livelihood of local population is further increasing (Shackleton et and nutrient acquisition, the water hyacinth is able to out-com- al. 2007). pete and displace submerged vegetation (Mitchell 1 985). The im- pact of the water hyacinth on the local lemur Hapalemur POTENTIAL OPPORTUNITIES. Some invasive plants have been alaotrensis remains up to now understudied. However, since H. in the landscapes for several generations, and instead of alaotrensis needs tall vegetation (cyperus) to cross water chan- being controlled or eradicated, they became part of the livelihood nels (Ralainasolo 2004), the potential isolation of tall vegetation and the well-being of human communities. In South Africa, for patches due to further spread of large water hyacinth mats might example, the prickly pear (Opuntia ficus-indica) is a source of food hinder genetic exchange between the populations of H. alaotren- (jam and the fruit itself), used for beverages (beer and syrup) or sis. Interestingly, H. alaotrensis was reported to feed on the stems for medicine and income for local traders (Beinart and Wotschela and flowers of the water hyacinth at Lake Alaotra (Birkinshaw and 2003, Shackleton et al. 201 1 ). In Nepal the invasive climbing weed Colquhoun 2003). Mikania micrantha is used by the local population as fuel wood As discussed by Rendigs et al. (201 5), the cumulative effects and fodder (Rai and Scarborough 201 3). In India, due to the unsuc- combined with the spreading of water hyacinth can lead to further cessful attempts to eradicate the tickberry (Lantana camara), the loss in fish and increasing the vulnerability of fishermen in the local communities addressed as adaptation strategy the use of Alaotra region. Regarding the impact of water hyacinth on the fi- this plant as source of income. In Madagascar, the use of the wa- shing activities at Lake Alaotra, 63% of the stakeholders conside- ter hyacinth as a source of raw material for handicrafts was initia- red waterway clogging as the main problem caused by the plant ted through the collaboration between the Government of on their livelihood since it decreases fish catches and destroys fi- Madagascar and the Embassy of Indonesia (Rakotomalala 201 4). shing material such as fishnets. The floating thick mats of water In the Alaotra wetlands, composting based on water hyacinth hyacinth are moved around by winds. These can also invade rice could represent a realistic possibility due to attributes such as its fields; suppressing rice crop, inhibiting rice germination and inter- relative short period of maturation (about 30 days), its ability to re- fering with rice harvest. These negative impacts have been shown tain nitrogen (N), phosphorus (P) and potassium (K) and thus to to cause important losses of rice paddies in West Bengal (EEA improve soil structure and nutrient contents (Polprasert et al. 201 2, Patel 201 2). At Lake Alaotra, this phenomenon can be obser- 1 980). The plant should be chopped into 5 cm long pieces and put ved frequently due to inefficient water control. The risk of produc- into piles with cow dung and other leaves before composting in tion loss due to the water hyacinth can become more prevalent in order to enhance microbial access (Dalzell et al. 1 979, Polprasert the near future; the water scarcity at the lake, combined with bad- et al. 1 980). Due to its high moisture content (90%), Elserafy (1 980) ly maintained irrigation systems are pushing the rice fields closer stated that composting water hyacinth does need only little into the marshlands. amount of water but should be covered or performed in pits to Another factor adding to the water issue is the high evapo- avoid excessive water loss in compost pile. Since composting re- transpiration demand of this invader, which can exceed by ten quires time and workload investments, local stakeholders from times the one by open water bodies (Gopal 1 987). Increased water the Alaotra region prefer to use directly cow dung instead. Despite MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 33
the relative ‘short’ duration of maturation of water hyacinth com- tion of water hyacinth in the diet (1 5–23%). Sixty years ago, fish post, this is already perceived as a long term investment for the farming was introduced by the Department of Forests and Water interviewees and thus represents a potential barrier to its adop- in the Alaotra with 85,000 ponds (each pond about 235 m2) cove- tion. In comparison to developed countries where farmers often ring an area of 2,000 ha and collapsed to 1 0,000 ponds in 1 984 possess health and production insurance (cf. Fisher et al. 2002), (Pidgeon 1 996). In comparison during the same period integrated the rural poor farmers of the Alaotra region are less resilient to rice-fish culture within villages covered only some 400 ha (Kiener eventual shocks such as drought, floods, landslides, crop pests, 1 963). Nowadays for the Alaotra region, fish breading has lost its market collapse, health problems and accidents (affecting house- importance (Anonymous 201 0). Currently, only one private compa- holds and individuals). Especially the direct dependence on rice ny in Anosiboribory produces alevin of Tilapia niloticus and Cypri- and fish production as main source of food or cash income leads nus carpio to supply the very few pisciculturists around Lake to increased vulnerability due to the unpredictability of production Alaotra (Bary-Jean Rasolonjatovo, pers. comm.). The limiting factor and price fluctuations, with the latter depending oftentimes on for pisciculturists is the water supply in the Alaotra. The low pro- outside drivers such as the national demands for the products or portion of water hyacinth in fish diet and the negligence of pisci- the season influencing the road conditions. As an adaptation to culturists in the region limit the use of the plant as fish food. these high uncertainties, mutual aid groups give relative insurance However fish farming may gain momentum given the lake fish and flexibility to the Alaotra farmers especially during hard times catches have dropped by about half (i.e., by about 2,000 t) within (Ducrot and Capillon 2004). However, the dissolution of mutual aid the last fifty years while human population has increased more group can be traumatic for poor-equipped farmer (ibid). The high than five times in the same period (Razanadrakoto 2004). exposure to risks for the local farmers can reduce or inhibit in- Water hyacinth can be used as raw material for making han- vestment in time demanding innovations and prevent long term dicraft and furniture (Ndimele 201 1 ). Long stems of water hyacinth perspectives. This is supported by our results; only 1 6% of the sta- (≥ 70 cm) are collected and sun-dried. The stalks should be com- keholders showed an opportunistic attitude towards the water pletely dry (Jafari 201 0). However, the only use of the stem does hyacinth. Another limitation for composting in developing coun- not allow successful infestation reduction and the market for tries is probably the intense workload for transporting large these products is far too small to have any impact on water hya- amounts of fresh water hyacinth (Gunnarsson and Petersen 2007). cinth populations (UNEP 201 3). Nonetheless, it could improve cash According to a vegetable farmer “(…) the only possibility to in- income at least for the handicraft makers of the Alaotra. The re- volve people [in the Alaotra region] to use the water hyacinth as duction of sedges and reeds utilization for handicraft can alleviate compost is to process it via a small factory where people can pressure on the critically endangered lemur H. alaotrensis feeding work and compost can be sold”. mainly on those plant species (Ratsimbazafy et al. 201 3, Waeber An alternative to composting could be the use of green ma- et al. In press). nure out of water hyacinth to reduce the labor requirements due Due to its high moisture content (90%) and its high ash pro- to the usage of dried material (Gunnarsson and Petersen 2007). duction (40% of dry weight) using water hyacinth as charcoal is Green manuring consists of spreading plant material (with high ni- unattractive because its incineration produces only 1 .3 kJ/m3 in trogen content) on the fields or working it into the soil (Stopes et comparison to 9.8 kJ/m3 for firewood (Thomas and Eden 1 990). al. 1 995). The green manure could be the most feasible alternative However, briquettes out of this plant produce 8.6 kJ/m3 which is for farmers in the Alaotra region. Due to its high ash content (40% comparable to charcoal (9.6 kJ/m3) (ibid). In the Philippines, a of dry weight, Thomas and Eden 1 990), the water hyacinth can al- company supplies local restaurants with briquettes (Laguador et so be burnt and used as mineral fertilizer. Ashes from water hya- al. 201 3). The process of making briquettes is relatively simple but cinth could be applied in the fields to provide minerals, mainly requires material (burning, briquetting and drying machines) (ibid). phosphorus (P) and potassium (K). The ash spreading would re- Meier (2008) concluded that using water hyacinth briquettes at quire a relatively low labor input; however, the effects and applica- Lake Alaotra is not efficient since it produces too much ash and tion rate must be investigated (Gunnarsson and Petersen 2007). smokes therefore reducing its calorific performance and repre- Thanks to its high content in crude protein (20%) (Abdelha- senting a threat for human health. Also, it does not suit to the lo- mid and Gabr 1 991 ), the water hyacinth is excellent as fodder for cal used cooking oven and requires more preparation time and ruminant animals (Tag El-Din 1 992). However, the air filled tissues effort in comparison to the charcoal. Moreover a mechanical of water hyacinth lead to high consumption of water by the ani- press machine is needed to reduce those latter cited preparations mal, therefore decreasing the nutritional value of the diet. The cal- but it would not be likely affordable for the local population (from cium oxalate occurring in its tissues represents a potential harm US$ 2,000). for the animal digestive tract in case of low amount of digestive Water hyacinth can be used to produce ethanol, methane acid (Bolenz et al. 1 990). The water hyacinth should be chopped and sludge. The ethanol is produced by hydrolyze and fermenta- into pieces to reduce air and negate water absorption. The mate- tion of water hyacinth. However, pretreatment is necessary due to rial should be pressed, centrifuged and washed with acid to elimi- the lack of yeast fermentable sugar within the plant (Thomas and nate the calcium oxalate (Bolenz et al. 1 990). Some Alaotra Eden 1 990). In China, the plant is mixed with pig manure to pro- farmers are already feeding their pigs with this plant, but at cur- duce biogas (Lu et al. 201 0). Biogas is generated by the degrada- rent stage it is unclear to what degree it is used. However, inclu- tion of organic material through anaerobic biological process. Due ding water hyacinth in the diet of pigs and geese could at least to high content of lignin in water hyacinth tissues, thermochemi- reduce the cost of animal food. cal pretreatment such as addition of ions is needed (Gunnerson Water hyacinth can be used as part of fish diet (Tilapia spp. , and Stuckey 1 986, Patel et al. 1 993). The remaining sludge can be Cyprinus carpio) (Igbinosun et al. 1 988, Mohapatra and Patra used as fertilizers due to its high concentration of nutrients (Hons 201 3); this however, showed limited application with low propor- et al. 1 993). The transportation of the sludge would represent MADAGASCAR CONSERVATION & DEVELOPMENT VOLUME 1 0 | ISSUE S3 — OCTOBER 201 5 PAGE 1 34
important labor force requirements due to its high water content version of this manuscript. This research was financially support (Gunnarsson and Petersen 2007). Producing ethanol, biogas and by the Stifterverband für die Deutsche Wissenschaft. sludge out of the water hyacinth in the Alaotra wetlands is limited by technical and financial requirements since they need important REFERENCES transfer of technology and infrastructure. Anonymous 201 0. Rapport de Mise en Œuvre des Priorités Régionales. 201 0. Ré- Madagascar belongs to the category of low human develop- gion Alaotra Mangoro. Unpubl. report. Cellule Régionale de Centralisation et d’Analyse. ment countries with a HDI (Human Development Index) of 0.483, ranked as 36th poorest country in the world (UNDP 201 3). In a Abdelhamid, A. M. and Gabr, A. A. 1 991 . Evaluation of water hyacinth as a feed for ruminants. Archives of Animal Nutrition 41 , 8–9: 745–756. system where input credit, crop production and health insurances (doi:1 0.1 080/1 74503991 0942851 9) are not sufficient or missing, stakeholders adopt their own strate- Andrianandrasana, H. T., Randriamahefasoa, J., Durbin, J., Lewis, R. E. and Ratsim- gies to manage covariant and idiosyncratic risks (e.g., weather un- bazafy, J. H. 2005. Participatory ecological monitoring of the Alaotra wet- certainty or illness, respectively) (Devereux 2001 ). Peasants in the lands in Madagascar. Biodiversity and Conservation 1 4, 1 1 : 2757–2774. Alaotra region depend mainly on fishing and rice cultivation; ho- (doi:1 0.1 007/s1 0531 -005-841 3-y) wever, diversification of activities, land tenure flexibility and mu- Bakoariniaina, L. N., Kusky, T. and Raharimahefa, T. 2006. Disappearing Lake Alao- tual aid are used to buffer uncertainties effects (cf. Ducrot and tra: Monitoring catastrophic erosion, waterway silting, and land degradation Capillon 2004). Governmental administrations in collaboration with hazards in Madagascar using Landsat imagery. Journal of African Earth Sciences 44, 2: 241 –252. (doi:1 0.1 01 6/j.jafrearsci.2005.1 0.01 3) NGOs should increase effort to help poor farmers to increase their Beinart, W. and Wotshela, L. 2003. Prickly pear in the Eastern Cape since the capabilities to improve their assets and to cope with risks, stress 1 950s: Perspectives from interviews. Kronos: Journal of Cape History 29: and shocks affecting their livelihood. In the near future, fish and 1 91 –209. rice production will likely drop continuously with increasing an- Bernard, H. R. 2005. Research Methods in Anthropology. Qualitative and Quantita- thropogenic pressures and degradation in the Lake Alaotra. In- tive Approaches. Altamira Press, Walnut Creek, California. vesting into new technologies or adoption of new resource use Binggeli, P. 2003. Pontederiaceae, Eichhornia crassipes, Water hyacinth. In: The could represent additional buffers and increase resilience of Natural History of Madagascar. S. M. Goodman and J. P. Benstead (eds.), pp farmers to an uncertain future. However, this would require in- 476–478. The University of Chicago press, Chicago and London. creased and concerted educational efforts to raise the awareness Birkinshaw, C. R. and Colquhoun, I. C. 2003. Lemur food plants. In: The Natural for environment and its potentials such as the usage of water History of Madagascar. S. M. Goodman and J. P. Benstead (eds.), pp hyacinth (cf. Reibelt et al. 201 4). 1 207–1 220. The University of Chicago press, Chicago and London. Bolenz, S., Omran, H. and Gierschner, K. 1 990. Treatments of water hyacinth tissue CONCLUSION to obtain useful products. Biological Wastes 33, 4: 263–274. (doi:1 0.1 01 6/0269-7483(90)901 30-K) The livelihoods of local stakeholders can benefit from using water hyacinth but only to some degree. Based on limited access to Calvert, P. 2002. Water Hyacinth Control and Possible Uses. Technical Brief. Inter- national Technology Development Center, U.K. Available at cash and technology, the most feasible uses are green manure,
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